suchna sahayak syllabus

1. www.onlinejobstudy.com Local Area Network (LAN) oLAN is a computer network that spans a relatively small area. Most LANs are confined to a single building or group of buildings. However, one LAN can be connected to other LANS over any distance via telephone lines and radio waves. A system of LANs connected in this way is called a wide-area network (WAN). oMost LANs as shown in Figure connect workstations and personal computers. Each node (individual computer) in a LAN has its own CPU with which it executes programs, but it is also able to access data and devices anywhere on the LAN. This means that many users can share expensive devices, such as laser printers, as well as data. Users can also use the LAN to communicate with each other, by sending e-mail or engaging in chart sessions. oThere are many different types of LANs-token-ring networks, Ethernets, and ARCnets being the most common for PCs. FDDI (Fiber Distributed Data Interface) is faster LAN. oLANs are capable of transmitting data at very fast rates, much faster than data can be transmitted over a telephone line; but the distance are limited, and there is also a limit on the number of computers that can be attached to a single LAN. www.onlinejobstudy.com

2. Figure: LAN Main Points: oGroup of interconnected computers within a small area. (Room, building, campus) oTwo or more pc's can from a LAN to share files, folders, printers, applications and other devices. oCoaxial or CAT 5 cables are normally used for connections. oDue to short distances, errors and noise are minimum. oLANs are restricted in size, which means that their worst-case transmission time is bounded and known in advance. Hence this is more reliable as compared to MAN and WAN. oData transfer rate is 10 to 100 mbps. oDistinguished on their transmission media and topology. oExample: A computer lab in a school and in a corporate company. LAN typically used transmission technology consisting of single cable to which all machines are connected. The most common LAN topologies are bus, ring and star. A typical LAN is shown in Figure: www.onlinejobstudy.com

3. Wide Area Network (WAN): A WAN is a computer network that spans a relatively large geographical area. Typically, A WAN consists of two or more local-area networks (LANs). Computers connected to a wide-area network are often connected through public networks, such as the telephone system. They can also be connected through leased lines or satellites. The largest WAN in existence is the Internet. Main Points: oDesign to extend over a large area like country and worldwide network. oConnecting number of LAN's to form larger network, so that resources can be shared. oContains multiple LAN's and MAN's. oNetworks can be up to 5 to 50 km. www.onlinejobstudy.com

4. oOwned by organization or individual. oData transfer rate is low compare to LAN. oExample: Organization with different branches located in the city. oDistinguished in terms of geographical range. oUses satellites and microwave relays. oData transfer rate depends upon the ISP provider and varies over the location. oIn contrast to LANs, WANs may utilize public, leased or private communication devices, usually in combinations, and can therefore span an unlimited number of miles as shown Figure : www.onlinejobstudy.com

5. Metropolitan Area Network (WAN): o Metropolitan Area Network (MAN) covers larger geographic area such as cities or districts. By interconnecting smaller networks within a large geographic area, information is easily transferred throughout the network. Local libraries and government agencies often use a MAN to connect to citizens and private industries. It may also connect MANs together within a larger area than LAN. The geographical limit of a MAN may span a city. Below is picture of MAN: www.onlinejobstudy.com